It is already generally known, especially for production processes in progress, how to compare the nominal values which are preset or calculated by a control system to the actual values of the tool so as to perform an adjustment of the actual values. Such is also described by CH 425 958. In highly dynamic processes with several functionally interrelated axes, however, this regulating procedure is not applicable, since for example it takes around four working and computing clock periods from the time the control system sends the nominal value to the drive, until the actual positioning of the drive occurs. As a rule, furthermore, the control system produces a separate pilot value, which influences the settings of the drive or the control current of the drive in the desired manner. Thus, the nominal values and the respective actual values can no longer be matched up and compared.
Thus far, the work piece after being manufactured has been optically or mechanically measured, thus drawing a conclusion as to any deviations during the manufacturing process.
WO 02/37168 A describes a method for controlling a 4-axis (Z, Z′, C, X) chip removal machine, in which a functional relation of the form Z=f(C, X) exists. It describes a “feedforward” control system which does not envision the differential value of the invention.